NumberFormatException while converting string to Integer

I'm getting integers of two EditText and on one of them textWatch is applied, multiplying them and setting text to another EditText. it normally works fine but when one of edit field become empty while hitting backspace app crashes.

java.lang.NumberFormatException: Invalid int: "" at
java.lang.Integer.invalidInt(Integer.java:138) at
java.lang.Integer.parseInt(Integer.java:358) at
java.lang.Integer.parseInt(Integer.java:334) at
com.example.fani.project.MainActivity$2.onTextChanged(MainActivity.java:90)
at android.widget.TextView.sendOnTextChanged(TextView.java:7679) at
android.widget.TextView.handleTextChanged(TextView.java:7739)